1. Field of Invention
The present invention relates to an method for creating a index of the data blocks, and more particularly to an index method for creating correspondingly a data block generated after a segmentation procedure of data de-duplication, applicable in a data de-duplication procedure.
2. Related Art
Data de-duplication is a data reduction technology, which is usually used in a disk-based backup system with a main purpose of reducing a storage capacity used in a storage system. The operation mode thereof is to search for duplicate and variable-sized data blocks at different locations in different files during a certain time period. The duplicate data blocks are replaced by indicators. Since the storage system is always full of a large amount of redundant data, in order to solve the problem and save more space, the de-duplication technology naturally becomes the focus of attention. The de-duplication technology can reduce the stored data to 1/20 of the original, thus providing larger backup space, so that the backup data can be maintained in the storage system for a longer time, and a large amount of bandwidth required during offline storage is saved.
FIG. 1 is a schematic view of access of data de-duplication in the prior art. In order to effectively control the stored file data, the data block of each input file is recorded through a Hash list in a server. Hash values corresponding to the data blocks are recorded in the Hash list. Since Hash algorithm has the feature of one-way transformation, each data block necessarily has only one group of unique Hash values. Through this feature, the de-duplication procedure regards data blocks having the same Hash value as same data blocks, so only one data block needs to be stored in a storage device and the corresponding relation of the same data blocks in different files is recorded.
However, with the increasing data quantity, the length of the Hash list increases accordingly, so the memory-loading time of the Hash list and the time for searching the Hash list are also increased.